.xbHead{
    text-align: center;
    float: left;
    width: 80%;
    margin-left: 10%;
    height: 50px;
    top: 50%;
    margin-top: 150px;
    text-align: center;
    padding-top: 50px;
    padding-bottom: 50px;
    background: aquamarine;
}
.xbWorld{
    float: left;
    width: 40%;
    margin-left: 30%;
    height: 100px;
    top: 50%;
    margin-top: 100px;
    text-align: center;
    padding-top: 50px;
    padding-bottom: 100px;
    background: antiquewhite;
}
.hide{
    display: none;
}
a{
    font-size: 24px;
}
.btn{
    float: right;
}